Eickhoff, M; Obst, M; Schröder, C; Hitchcock, AP; Tyliszczak, T; Martinez, RE; Robbins, LJ; Konhauser, KO; Kappler, A: Nickel partitioning in biogenic and abiogenic ferrihydrite: The influence of silica and implications for ancient environments, Geochimica et Cosmochimica Acta, 140, 65-79 (2014), online: 24.05.2014, doi:10.1016/j.gca.2014.05.021 [Link]
Abstract:

Fe(III) (oxyhydr)oxides are ubiquitous in modern soils and sediments, and their large surface area leads to scavenging of trace elements. Experimental trace element partitioning between Fe(III) (oxyhydr)oxides and aqueous solutions have been used to elucidate the geochemical composition of the Precambrian oceans based on the trace element concentrations in Pre- cambrian banded iron formations (BIFs). However, previous partitioning experiments did not consider the potential influence of microbially-derived organic material, even though it is widely believed that bacterial phytoplankton was involved in Fe(II) oxidation and the deposition of BIF primary minerals. Therefore, the present study focuses on sorption of Ni to, and co-precipitation of Ni with, both biogenic ferrihydrite precipitated by the freshwater photoferrotroph Rhodobacter ferrooxi- dans SW2 and the marine photoferrotroph Rhodovulum iodosum, as well as chemically synthesized ferrihydrite. We considered the influence of cellular organic material, medium composition and the availability of dissolved silica. Our results show a pref- erential association of Ni with ferrihydrite, and not with the microbial cells or extracellular organic substances. We found that the addition of silica (2 mM) did not influence Ni partitioning but led to the encrustation of some cells with ferrihydrite and amorphous silica. The two- to threefold lower Ni/Fe ratio in biogenic as compared to abiogenic ferrihydrite is probably due to a competition between Ni and organic matter for sorption sites on the mineral surface. Additionally, the competition of ions present at high concentrations in marine medium for sorption sites led to decreased Ni sorption or co-precipitation. Based on our data we conclude that, if the Fe(III) minerals deposited in BIFs were – at least to some extent – biological, then the Ni concentrations in the early ocean would have been higher than previously suggested. This study shows the importance of con- sidering the presence of microbial biomass and seawater ions in paleomarine reconstructions.

Aktuelle Termine

BayCEER-Kolloquium:
Do. 17.10.2019
The dark side of plants: Monitoring spatio-temporal dynamics of roots by non-invasive technologies
Do. 24.10.2019
Inside the fog: towards an improved forecasting of nocturnal fog by using turbulence-resolving simulations
Ökologisch-Botanischer Garten:
So. 20.10.2019
Der ÖBG zum Kennenlernen: Allgemeine Gartenführung
So. 03.11.2019
Bittersüßer Wohlgeschmack: "Kolonialpflanzen"
So. 03.11.2019
Ausstellungseröffnung: Farben-Pflanzen-Pflanzenfarben - Malerei von Angelika Gigauri
BayCEER Blog
24.05.2019
Stoichiometric controls of C and N cycling
07.05.2019
Flying halfway across the globe to dig in the dirt – a research stay in Bloomington, USA
07.05.2019
EGU – interesting research and free coffee
16.04.2019
Picky carnivorous plants?
RSS Blog als RSS Feed
Wetter Versuchsflächen
Luftdruck (356m): 963.4 hPa
Lufttemperatur: 14.7 °C
Niederschlag: 0.0 mm/24h
Sonnenschein: 5 h/d
Wind (Höhe 17m): 9.8 km/h
Wind (Max.): 20.2 km/h
Windrichtung: SO

...mehr
Globalstrahlung: 285 W/m²
Lufttemperatur: 12.3 °C
Niederschlag: 0.2 mm/24h
Sonnenschein: 2 h/d
Wind (Höhe 32m): 14.8 km/h

...mehr
Diese Webseite verwendet Cookies. weitere Informationen